Optical tweezers (originally called single-beam gradient force trap) are scientific instruments that use a highly focused laser beam to provide an attractive or repulsive force (typically on the order of piconewtons), depending on the relative refractive index between particle and surrounding medium; these forces can be used to physically hold and move microscopic objects, in a manner similar to tweezers. They are able to trap and manipulate small particles, whose size is typically in microns, including dielectric and absorbing particles. Optical tweezers have been particularly successful in studying a variety of biological systems in recent years.
Thomas Gold (also known as Tommy Gold), (May 22, 1920 – June 22, 2004) was an Austrian-born astrophysicist, a professor of astronomy at Cornell University, a member of the U.S. National Academy of Sciences, and a Fellow of the Royal Society (London). Gold was one of three young Cambridge scientists who in 1948 proposed the now mostly abandoned "steady state" hypothesis of the universe. Gold's work crossed academic and scientific boundaries, into biophysics, astronomy, aerospace engineering, and geophysics.
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